Circuit, component and equipment for avoiding false triggering of latch-up protection

Abstract

The utility model discloses a circuit, a component and equipment capable of avoiding false triggering latch-up protection. A cathode of a voltage stabilizing source is connected with a first transmitting end of an optocoupler; the anode of the voltage stabilizing source and the second end of the third resistor are grounded; the reference end of the voltage stabilizing source is connected with the second end of the first resistor; the first end of the second resistor is connected with a power supply VCC, and the second end of the second resistor is connected with the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected with the first end of the third resistor, and the second end of the first capacitor is grounded. Therefore, during starting, the delay sub-circuit prevents starting current from mistakenly triggering latch-up protection, and after starting is finished, the short-circuit protection module starts to work, so that false triggering of short-circuit protection can be avoided, and normal starting of the power supply module is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and in particular to a circuit, a component and a device for preventing false triggering of a lockout protection. Background Art

[0002] As a power supply unit connected to the device in the form of a module, the power module is widely used in various fields due to its high efficiency and easy installation and expansion. When the power module is in use, the circuit may have an abnormal increase in current. At this time, the electronic components inside the power supply may be seriously damaged or even burned. In order to deal with this risk, some advanced control chips are designed with automatic locking function. The core function of the locking function is to quickly cut off the power output when a short circuit is detected in the circuit to prevent overload current from passing through the circuit, thereby protecting key components from damage.

[0003] However, the instantaneous current when the power module starts up can easily exceed the rated current, erroneously triggering the short-circuit protection and thus locking the chip, affecting the normal startup of the power module. Summary of the invention

[0004] In view of the above problems, the utility model provides a circuit, component and device for avoiding false triggering of lockout protection. When the instantaneous current at the startup of the power module exceeds the rated current, false triggering of short-circuit protection can be avoided to ensure normal startup of the power module.

[0005] According to a first aspect of the utility model, a circuit for avoiding false triggering of lockout protection is provided, comprising:

[0006] Latching subcircuit and delay subcircuit;

[0007] The locking subcircuit comprises: a short circuit protection module and an optical coupler connected to the short circuit protection module;

[0008] The delay subcircuit includes: a voltage stabilizing source, a first resistor, a second resistor, a third resistor and a first capacitor;

[0009] Among them, the cathode of the voltage-stabilizing source is connected to the first transmitting end of the optocoupler; the anode of the voltage-stabilizing source is grounded; the reference end of the voltage-stabilizing source is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded.

[0010] Optionally, the locking subcircuit further includes a fourth resistor, a fifth resistor, a sixth resistor and a second capacitor;

[0011] Among them, the short-circuit protection module is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the second transmitting end of the optocoupler; the third output end of the optocoupler is connected to the power supply VDD, and the fourth output end of the optocoupler is connected to the first end of the fourth resistor; the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded; the first end of the second capacitor is connected to the first end of the fifth resistor, and the second end of the second capacitor is grounded; the first end of the fifth resistor is connected to the locking pin of the chip.

[0012] Optionally, the steady-state voltage value of the first capacitor is determined according to the resistance values ​​of the second resistor and the third resistor.

[0013] Optionally, the steady-state voltage value of the first capacitor is determined based on the following formula:

[0014]

[0015] Wherein, u is the steady-state voltage value of the first capacitor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, VCC is the voltage of the power supply VCC, C1 is the first capacitor, and t is the charging time of the first capacitor.

[0016] Optionally, the power loss of the second resistor and the third resistor is less than or equal to a loss threshold.

[0017] Optionally, the first resistor is used to suppress the input current of the voltage stabilization source.

[0018] According to a second aspect of the present invention, a component is provided, comprising the aforementioned circuit.

[0019] According to a third aspect of the utility model, a device is provided, comprising the aforementioned circuit.

[0020] The above one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0021] The embodiments of this specification provide a circuit, component and device for avoiding false triggering of lockout protection, by connecting the cathode of the voltage stabilizer to the first transmitting end of the optocoupler; the anode of the voltage stabilizer is grounded; the reference end of the voltage stabilizer is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded. Therefore, when the power module is started, the delay subcircuit can be used to avoid the startup current from falsely triggering the lockout protection, and after the power module is started, the short-circuit protection module starts to work, thereby avoiding false triggering of the short-circuit protection and ensuring the normal startup of the power module.

[0022] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Various other advantages and benefits will become apparent to those skilled in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference figures are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0024] Figure 1 A schematic structural diagram of a circuit for avoiding false triggering of lockout protection in an embodiment of the utility model is shown.

[0025] Figure 2 The structure diagram of the components in the embodiment of the utility model is shown.

[0026] Figure 3 The structure diagram of the device in the embodiment of the utility model is shown. DETAILED DESCRIPTION

[0027] In the prior art, since the instantaneous current at the startup of the power module easily exceeds the rated current, the short-circuit protection may be mistakenly triggered and the chip may be locked, thus affecting the normal startup of the power module.

[0028] Taking the chip L6599 as an example, its latch pin DIS is internally connected to a comparator. When the voltage on the pin exceeds 1.85V, the comparator shuts down the chip and makes its power consumption almost reach the "pre-startup" level. At this time, the information is latched and the power supply of the chip must be turned off to enable it to restart. When the voltage on the chip VCC pin is lower than the UVLO threshold, the latch is removed. When the short-circuit protection module detects that the current exceeds the preset threshold, the conventional protection circuit outputs a high level, thereby turning on the optocoupler, and the chip's latch pin DIS voltage exceeds the 1.85V threshold, thereby locking the chip until the power module is powered on again. However, the instantaneous current at the startup of the power module can easily exceed the rated current, erroneously triggering the short-circuit protection and then locking the chip, affecting the normal startup of the power module.

[0029] Based on this, the embodiments of the utility model solve the technical problem in the prior art that when the power module is started, the short circuit protection is falsely triggered, resulting in the power module being unable to start normally by providing a circuit, components and equipment for avoiding false triggering of the lockout protection.

[0030] The technical solution of the embodiment of the utility model is to solve the above technical problems, and the overall idea is as follows:

[0031] A circuit for preventing false triggering of a lockout protection, comprising:

[0032] Latching subcircuit and delay subcircuit;

[0033] The locking subcircuit comprises: a short circuit protection module and an optical coupler connected to the short circuit protection module;

[0034] The delay subcircuit includes: a voltage stabilizing source, a first resistor, a second resistor, a third resistor and a first capacitor;

[0035] Among them, the cathode of the voltage-stabilizing source is connected to the first transmitting end of the optocoupler; the anode of the voltage-stabilizing source is grounded GND1; the reference end of the voltage-stabilizing source is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded GND1, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded GND1.

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] First of all, the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0038] Embodiment 1

[0039] Combination Figure 1 As shown, the embodiment of the utility model provides a circuit for avoiding false triggering of lockout protection, which specifically includes: a lockout subcircuit and a delay subcircuit;

[0040] The latching subcircuit includes: a short-circuit protection module and an optocoupler connected to the short-circuit protection module; an optocoupler is also called a photoelectric coupler, which transmits electrical signals using light as a medium and has a good isolation effect on input and output electrical signals. The optocoupler mainly includes three parts: light emission, light reception, and signal amplification. The input electrical signal drives the diode to emit light of a certain wavelength, and the light detection receiver generates a photocurrent, which is output after amplification, thereby completing the electrical-optical-electrical conversion, thereby playing the role of input and output isolation.

[0041] The delay subcircuit includes: a voltage stabilizing source, a first resistor, a second resistor, a third resistor and a first capacitor.

[0042] Among them, the cathode of the voltage-stabilizing source is connected to the first transmitting end of the optocoupler; the anode of the voltage-stabilizing source is grounded GND1; the reference end of the voltage-stabilizing source is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded GND1, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded GND1.

[0043] In an optional implementation, the latching subcircuit further includes a fourth resistor, a fifth resistor, a sixth resistor and a second capacitor;

[0044] Among them, the short-circuit protection module is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the second transmitting end of the optocoupler; the third output end of the optocoupler is connected to the power supply VDD, and the fourth output end of the optocoupler is connected to the first end of the fourth resistor; the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded GND; the first end of the second capacitor is connected to the first end of the fifth resistor, and the second end of the second capacitor is grounded GND; the first end of the fifth resistor is connected to the locking pin of the chip.

[0045] In this embodiment, when the short-circuit protection module detects that the current exceeds the preset threshold, it outputs a high level. After the delay, the optocoupler is turned on, and the lock pin DI S of the control chip exceeds the threshold. The chip is locked until the power module is powered on again.

[0046] In addition, the auxiliary circuit provides a power supply VCC to charge the first capacitor C1 and slowly increase the voltage until it exceeds the comparison threshold of the voltage regulator source, for example, the comparison threshold is 2.5V. When the voltage across the first capacitor C1 is initially lower than the comparison threshold of 2.5V, the current flowing through the voltage regulator source is a cut-off current. Even if the short-circuit protection of the short-circuit protection module is triggered, the optocoupler cannot be turned on, thereby preventing the startup current from falsely triggering the short-circuit protection function. When the voltage across the first capacitor C1 exceeds the comparison threshold of 2.5V, the voltage regulator source is fully turned on, and the short-circuit protection function is no longer restricted. That is, the startup of the power module is completed, and the short-circuit protection module starts the short-circuit protection work.

[0047] In the delay subcircuit, the first resistor R1 is used to suppress the input current of the voltage regulator, and the ratio of the second resistor R2 to the third resistor R3 determines the steady-state voltage value of the first capacitor C1. The first resistor R1 is used to suppress the input current Iref of the voltage regulator. Assuming that the voltage across the first capacitor C1 is 3V in the steady state, it is necessary to satisfy R1>3 / I ref.

[0048] Furthermore, the ratio of the second resistor R2 to the third resistor R3 determines the steady-state voltage value of the first capacitor C1. In this embodiment, the steady-state voltage value is set to 3V, and R2 / R3=VCC / 3-1.

[0049] According to the resistance values ​​of the second resistor and the third resistor, the steady-state voltage value of the first capacitor can be determined based on the following formula:

[0050]

[0051] Wherein, u is the steady-state voltage value of the first capacitor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, VCC is the voltage of the power supply VCC, C1 is the first capacitor, and t is the charging time of the first capacitor.

[0052] If the short-circuit protection shielding time is assumed to be Tset, the above formula can be obtained:

[0053]

[0054] Considering the power loss of the second resistor R2 and the third resistor R3, assuming that the loss is to be less than or equal to the loss threshold, for example, the loss threshold is 0.1W, then:

[0055] R2+R3≥10VCC 2

[0056] According to the above formula, the required parameters can be calculated. Assuming VCC = 12V, Tset = 30ms, then R2 = 30kΩ, R3 = 10kΩ, C1 = 2.2uF.

[0057] In summary, the embodiment of this specification provides a circuit for avoiding false triggering of the lockout protection, by connecting the cathode of the voltage stabilizer to the first transmitting end of the optocoupler; the anode of the voltage stabilizer and the second end of the third resistor to ground; the reference end of the voltage stabilizer is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded. Therefore, at startup, the startup current is prevented from falsely triggering the lockout protection through the delay subcircuit, and after the startup is completed, the short-circuit protection module starts to work, thereby avoiding false triggering of the short-circuit protection and ensuring the normal startup of the power module.

[0058] Embodiment 2

[0059] Based on the same inventive concept, Figure 2 As shown, this embodiment provides a component, including any circuit described in Embodiment 1.

[0060] Since the components introduced in this embodiment are components used in implementing the circuit for avoiding false triggering of the lockout protection in the embodiment of the present application, based on the circuit for avoiding false triggering of the lockout protection introduced in the embodiment of the present application, the technical personnel in this field can understand the specific implementation of the components of the present embodiment and its various variations, so how the components implement the method in the embodiment of the present application is not described in detail here. As long as the technical personnel in this field implement the components used in the circuit for avoiding false triggering of the lockout protection in the embodiment of the present application, they all belong to the scope of protection of the present application.

[0061] Embodiment 3

[0062] Based on the same inventive concept, Figure 3 As shown, this embodiment provides a device, including the circuit described in any one of the first embodiments.

[0063] Since the device introduced in this embodiment is a device used to implement the circuit for avoiding false triggering of the lockout protection in the embodiment of the present application, based on the circuit for avoiding false triggering of the lockout protection introduced in the embodiment of the present application, a person skilled in the art can understand the specific implementation of the electronic device of the present embodiment and its various variations, so how the device implements the method in the embodiment of the present application is not described in detail here. As long as a person skilled in the art implements the device used by the circuit for avoiding false triggering of the lockout protection in the embodiment of the present application, it belongs to the scope of protection of the present application.

[0064] In summary, the embodiments of this specification provide a circuit, component and device for avoiding false triggering of lockout protection, by connecting the cathode of the voltage stabilizer to the first transmitting end of the optocoupler; the anode of the voltage stabilizer and the second end of the third resistor to ground; the reference end of the voltage stabilizer is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded. Therefore, at startup, the startup current is prevented from falsely triggering the lockout protection through the delay subcircuit, and after the startup is completed, the short-circuit protection module starts to work, thereby avoiding false triggering of the short-circuit protection and ensuring the normal startup of the power module.

[0065] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0066] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A circuit for avoiding false triggering of lockout protection, characterized in that: include: Latching subcircuit and delay subcircuit; The locking subcircuit comprises: a short circuit protection module and an optical coupler connected to the short circuit protection module; The delay subcircuit includes: a voltage stabilizing source, a first resistor, a second resistor, a third resistor and a first capacitor; Among them, the cathode of the voltage-stabilizing source is connected to the first transmitting end of the optocoupler; the anode of the voltage-stabilizing source is grounded; the reference end of the voltage-stabilizing source is connected to the second end of the first resistor; the first end of the second resistor is connected to the power supply VCC, and the second end of the second resistor is respectively connected to the first end of the third resistor and the first end of the first resistor; the second end of the third resistor is grounded, the first end of the first capacitor is connected to the first end of the third resistor, and the second end of the first capacitor is grounded.

2. The circuit according to claim 1, characterized in that The latching subcircuit further includes a fourth resistor, a fifth resistor, a sixth resistor and a second capacitor; Among them, the short-circuit protection module is connected to the first end of the sixth resistor, and the second end of the sixth resistor is connected to the second transmitting end of the optocoupler; the third output end of the optocoupler is connected to the power supply VDD, and the fourth output end of the optocoupler is connected to the first end of the fourth resistor; the second end of the fourth resistor is connected to the first end of the fifth resistor, and the second end of the fifth resistor is grounded; the first end of the second capacitor is connected to the first end of the fifth resistor, and the second end of the second capacitor is grounded; the first end of the fifth resistor is connected to the locking pin of the chip.

3. The circuit according to claim 1, characterized in that The steady-state voltage value of the first capacitor is determined according to the resistance values ​​of the second resistor and the third resistor.

4. The circuit according to claim 3, characterized in that The steady-state voltage value of the first capacitor is determined based on the following formula: Wherein, u is the steady-state voltage value of the first capacitor, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, VCC is the voltage of the power supply VCC, C1 is the first capacitor, and t is the charging time of the first capacitor.

5. The circuit according to claim 1, characterized in that The power loss of the second resistor and the third resistor is less than or equal to a loss threshold.

6. The circuit according to claim 1, characterized in that The first resistor is used to suppress the input current of the voltage stabilization source.

7. The circuit according to claim 1, characterized in that The second resistor is 30 kΩ, the third resistor is 10 kΩ, and the first capacitor is 2.2 uF.

8. A component, characterized in that: The invention comprises the circuit described in any one of claims 1 to 6.

9. A device, characterized in that: The invention comprises a circuit as claimed in any one of claims 1 to 6.

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